Synthesis and characterization of phosphate glass microspheres for radiotherapy applications

Glass microspheres containing radioisotopes 90 Y or 32 P can be used for cancer radiotherapy. 90 Y and 32 P emit β - particles with short penetration range of about 2. 5 mm in living tissue with the half-life of respectively 2. 7 days and 14.3 days. Glass microspheres containing such radioisotopes with suitable activit y can be easily introduced in specific human organs as liver, stomach, pancreas, and uteru s to kill cancer cells, reducing significantly damages to other health tissues allow ing a major therapeutic effect. The use of Y2O3-Al 2O3-SiO 2 glass microspheres for cancer therapy is an effici ent alternative compared to conventional chemotherapy treatments. However, the activity of the glass microspheres with 90 Y is relatively low, due to the limitation of conte nt of Y 2O3 to only 17 mol %, and short half-life, in a way that 90 Y may decay substantially even before the treatment . A potential alternative is to produce microspheres with high co ntent of 31 P that could be transmuted to 32 P with higher activity and longer half-life than 90 Y. In the present work phosphate glass microspheres were produced with different compositions and particle size distribution in the range of 20 μm to 30 μm by using two different thermal processes to spher odize glass particles originally with irregular shapes. Samples were characterized by Differential Thermal Analysis, X-rays diffraction, and Energy Dispersive X-rays Fluorescence Spectroscopy. The glass dissolution rate in water was determined at 9 0 o C, and in Simulated Body Fluid (SBF) at 37 o C. Glasses with dissolution rates close to 10 -5 g/(cm 2 .d) were obtained, which make them suitable for the present application. Scanning Elec tron Microscopy was used to evaluate the shape of the microspheres before and after the diss olution tests. The cytotoxicity tests showed that these microspheres can be used for biological applications.